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What is Phantom Limb Pain?

Phantom Limb Pain or Phantom Painis the pain that appears to generate from the region of an amputated part in the body. It is described as a shooting or sharp, burning, aching and cramping pain. The pain is very difficult to treat. This type of pain is experienced by people who have had their leg or arm removed, but the pain may also occur in people who have undergone surgery to remove body parts such as eye, breast, penis or tongue.

The sensation that the limb is still there even after amputation is called phantom sensation. With this sensation the amputee may feel:

Numbness.

As if the missing limb is still existing, but in a funny position

Tingly.

As if the missing limb is shortening. This is known as telescoping.

Prickly.

As if the missing fingers and/or toes are moving.

Causes of Phantom Limb Pain:

Although the appropriate cause of this pain is still not known, brain and spinal cord are thought to be the pain generating areas. It was observed during an MRI (Magnetic Resonance Imaging) and /or PET (Positron Emission Tomography) that the brain showed activity in some areas when the patients experienced this pain.

Phantom Pain is thought to be the result of mixed signals sent out by the brain. Soon after an amputation of a body part, regular inputs from the missing part to the brain and spinal cord are lost and the result can be compared to tangled wires. Pain is the body’s basic message to convey “something is not right within the body.”

Brain Remapping – Because the amputated part cannot respond to the brain signals, some studies have shown that the brain directs these signals (remapping) to some other part of the body. For example: signals that are aimed at a missing leg could be now reaching an existing cheek. This in turn leads to the sensation that the missing leg is being touched, when in fact the cheek is touched. This could still lead to pain because it is a version of the tangled sensory wiring.

Scar tissue formation at the amputated area, damaged nerve endings and the physical memory of pre-amputation pain are some of the causes of this pain.

Symptoms of Phantom Limb Pain:

Patients feel the “phantom limb’s position” to be abnormal or twisted, which would be unbearably painful if the other existing limb were in that position.

Pain tends to appear in episodes, rather than appearing constantly.

Begins within the first week of amputation.

Pain is described as stabbing, squeezing, boring, burning or throbbing.

The pain seems to generate from the distant part of the amputated limb. For example: If one of the legs is removed, pain seems to come from the foot of the amputated leg.

Emotional stress, weather changes, fatigue, anxiety or putting pressure on the remaining part of the amputated limb may trigger the pain.

Risk Factors of Phantom Limb Pain:

These include:

Ill-fitting artificial limb.

Swelling in the existing leg or arm.

Pain before amputation – Patients who had pre-amputation pain continued to have it after amputation. This could be because of the retention of the pain memory by the brain. So, it keeps sending the pain signals even after the removal of the part.

Stump Pain – This pain is a result of an abnormal growth on damaged nerve endings known as neuroma. People who experience this pain also complain of Phantom Pain.

Treatment of Phantom Limb Pain:

Treating this condition could be difficult. The very first approach advised by doctors is pain-relieving medications followed by non-invasive techniques such as acupuncture. If the patient is not pain-free even after trying these options surgery is suggested.

Medications – No specific pain-killers are available for this pain, but it has been found that some medicines which are used to treat other conditions have succeeded in relieving pain associated with nerves. These include:

Anticonvulsant Drugs – These are used to treat nerve pain. Carbamazepine (Tegretol, Carbatrol) and Gabapentin (Neurontin) are some of the examples.

Antidepressants – Pamelor (Nortriptyline) and Amitriptyline fall under the category of tricyclic antidepressant drugs that can reduce the nerve pain. They modify the chemical messengers that send out pain signals.

Narcotics – Morphine and Codeine, the opioid medications when taken in appropriate and limited doses may help in controlling the Phantom Pain.

Non-Invasive Procedures – These include the following options:

Acupuncture – This is a technique where sterilized and very fine needles are inserted into specific points in the body. By doing so, the central nervous system gets stimulated and releases endorphins, the natural pain relievers.

Electric Artificial Limb – This is a kind of artificial limb. Also known as myoelectric prosthesis, it has electric signal controlled motors that are usually seen during the process of voluntary muscle activation in the remaining part of the amputated limb.

Stimulation of Nerves – Using a device that sends electric current through adhesive patches on the area of the skin that is experiencing pain, pain signals are masked and prevented from reaching the brain. This process is known as Transcutaneous Electrical Nerve Stimulation (TENS).

4. Mirror Box – As the name indicates, this particular device has mirrors that give an impression that the amputated limb exists. By inserting the intact limb and the stump into the 2 openings of the box, the patient performs exercises by moving the existing limb and imagining the movement of the missing limb. A significant number of people found this technique helpful in relieving the pain.

Invasive Techniques for Phantom Limb Pain:

These include minimally-invasive techniques such as spinal cord stimulation, injections and intrathecal delivery system (medication is delivered directly into the spinal fluid).

Surgical options such as neurectomy or stump revision and brain stimulation (current is passed into the brain through the insertion of electrodes) may provide pain-relief.

A novel approach to treat this condition is goggles. These special goggles are computer programmed in such a way that they mirror the patient’s intact limb giving an impression that the other limb has not been amputated. The patient then moves the virtual limb to perform various tasks.